I can't switch between animations
You need to select the armature and then change the action in the action editor. You created the animation for the armature, then applied it to the mesh object in the action editor by mistake. This doesn't do anything because the animation expects the transform hierarchy of the armature. You can check in the outliner where your animations are. They should only exist under the armature, not under the mesh objects.


Select Cube and remove the action in the action editor.
Select Cube.001 and remove the
action in the action editor.
Select Armature and choose the action you want to play and it
should work.